[Science Solitaire] Pain in a crab’s mentality
Many years ago, one of my closest friends sent me crabs from Calbayog, her hometown. Each could occupy a pasta plate about eight inches in diameter. I was not crazy about crabs but my late husband was. Also, I don’t cook, and as far as crabs were concerned, I only knew that when they turn red as you steam them, they are done.
I did not want to watch them before they turned red because even if I wasn’t sure they felt pain, just the thought they just might, bothered me.
As far as we knew then, science was not really sure if crabs felt pain. So I suspected that my husband took refuge in that research gap and ate crabs at a rate that would have driven them to extinction. But this species of crabs outlived my husband, and they lived to this point where an experiment by Bob Elwood and Barry Magee from Queen’s University Belfast confirmed that they do feel pain. Their study was recently published in the Journal of Experimental Biology.
There are two ways that we can sense something and scientists think it is that one which makes us avoid that thing again that tells us that it caused pain. Crabs and similar crustaceans like lobsters and crayfish and even prawns, do not have the kind of brain that mammals, including humans, do.
Crustaceans have a nervous system that has a pea-sized brain behind the eyes but also lots of other tiny “brain” specializing in controlling other functions located all over their bodies. They have nociceptors, that which makes them sense something that would immediately make them protect themselves instantly.
Then there are those other receptors which enable the crustaceans to sense something that makes them avoid that to protect themselves and more importantly, remember it. Elwood and Magee think that this latter receptor is this kind of sensing that tells us that pain is felt.
The researchers knew that crabs liked dark shelters so they decided to give some electrical shocks to those crabs who went to a particular shelter. By the third time the crabs felt the shocks, they avoided that shelter and explored other options. The researchers thought that for the crabs to give up something of value to them (shelter) could only be caused by something that they wanted to avoid and pain was very good candidate for this.
If some of you would feel that knowing this would shrink your options as to what seafood to eat, it would probably confuse you further to know that a recent study led by Professor James Rose from the University of Wyoming and published in the journal Fish and Fisheries found that fish do not feel pain.
In 2003, a study had suspected that they did since after injecting some acid solution to rainbow trout, it exhibited movements that seemed like they were experiencing discomfort, such as rubbing their mouths on the ground and swaying repeatedly. But this most recent study looked at the fish brains and found that there aren’t enough of pain receptors for fish to feel pain.
I felt relieved somewhat now knowing fish do not feel pain. I only went fishing once in my entire life and when I hooked a small grouper and I pulled my nylon string out of the water and saw the fish’s eyes and mouth wide open in an expression of what I could interpret as shock and pain, I really wanted to give it first aid. All the boatmen with me laughed out loud at my reaction. But I just could not fish anymore after that.
The two studies I think are very good examples of how science can just rip you from your worldview or from your long-held feelings about certain things like pain as experienced by other creatures. Other things like religion, a very good advertisement/campaign or and a very persuasive sales representative could do that to you too but science does it with evidence and largely, building upon the knowledge that came before it. That way, everyone can follow as long as they are thinking, and not just taking things in because they “felt right and true.” It is not a good idea to bank on feelings when you want to understand.
I think these findings should be spread to industry as well. I don’t think crabs will appreciate an apology but perhaps, we should consider adjusting our crab harvesting practices with this knowledge. Personally, I shall never look at a mixed seafood platter the same way again. - Rappler.com
Maria Isabel Garcia is a science writer. She has written two books, “Science Solitaire” and “Twenty One Grams of Spirit and Seven Ounces of Desire.” Her column appears every Friday and you can reach her at firstname.lastname@example.org.